Now showing items 1-13 of 13

    • A 2-D orientation-adaptive prediction filter in lifting structures for image coding 

      Gerek, Ö. N.; Çetin, A. Enis (Institute of Electrical and Electronics Engineers, 2006)
      Lifting-style implementations of wavelets are widely used in image coders. A two-dimensional (2-D) edge adaptive lifting structure, which is similar to Daubechies 5/3 wavelet, is presented. The 2-D prediction filter predicts ...
    • Adaptive polyphase subband decomposition structures for image compression 

      Gerek, Ö. N.; Çetin, A. Enis (IEEE, 2000)
      Subband decomposition techniques have been extensively used for data coding and analysis. In most filter banks, the goal is to obtain subsampled signals corresponding to different spectral regions of the original data. ...
    • Block wavelet transforms for image coding 

      Çetin, A. Enis; Gerek, Ö. N.; Ulukuş, Ş. (IEEE, 1993)
      In this paper, a new class of block transforms is presented. These transforms are constructed from subband decomposition filter banks corresponding to regular wavelets. New transforms are compared to the discrete cosine ...
    • An edge-sensing predictor in wavelet lifting structures for lossless image coding 

      Gerek, Ö. N.; Çetin, A. Enis (SpringerOpen, 2007)
      The introduction of lifting implementations for image wavelet decomposition generated possibilities of several applications and several adaptive decomposition variations. The prediction step of a lifting stage constitutes ...
    • Equiripple FIR filter design by the FFT algorithm 

      Çetin, A. Enis; Gerek, Ö. N.; Yardımcı, Y. (Institute of Electrical and Electronics Engineers, 1997-03)
      The fast Fourier transform (FFT) algorithm has been used in a variety of applications in signal and image processing. In this article, a simple procedure for designing finite-extent impulse response (FIR) discrete-time ...
    • Frequency band characteristics of tree-structured filter banks 

      Gerek, Ö. N.; Gürcan, M. N.; Çetin, A. Enis (The Institution of Engineering and Technology, 1996-04-11)
      A sub-band decomposition filter bank can be recursively used in a tree structure to divide the frequency domain into various subfrequency bands. The frequency bands of the sub-band signals have a counter intuitive order ...
    • Image denoising using adaptive subband decomposition 

      Gezici, Sinan; Yılmaz, İsmail; Gerek, Ö. N.; Çetin, A. Enis (IEEE, 2001)
      In this paper, we present a new image denoising method based on adaptive subband decomposition (or adaptive wavelet transform) in which the filter coefficients are updated according to an Least Mean Square (LMS) type ...
    • Lossless image compression using an edge adapted lifting predictor 

      Gerek, Ö. N.; Çetin, A .Enis (IEEE, 2005-09)
      We present a novel and computationally simple prediction stage in a Daubechies 5/3 - like lifting structure for lossless image compression. In the 5/3 wavelet, the prediction filter predicts the value of an odd-indexed ...
    • Motion-compensated prediction based algorithm for medical image sequence compression 

      Oǧuz, S. H.; Gerek, Ö. N.; Çetin, A. Enis (Elsevier BV, 1995-09)
      A method for irreversible compression of medical image sequences is described. The method relies on discrete cosine transform and motion-compensated prediction to reduce intra- and inter-frame redundancies in medical image ...
    • Nonlinear subband decomposition structures in GF-(N) arithmetic 

      Gürcan, M. N.; Gerek, Ö. N.; Çetin, A. Enis (Elsevier BV, 1998-01-30)
      In this paper, perfect reconstruction filter bank structures for GF-(N) fields are developed. The new filter banks are based on the nonlinear subband decomposition and they are especially useful to process binary images ...
    • Polyphase adaptive filter banks for fingerprint image compression 

      Gerek, Ö. N.; Çetin, A. Enis (The Institution of Engineering and Technology, 1998-10-01)
      A perfect reconstruction polyphase filter bank structure is presented in which the filters adapt to the changing input conditions. The use of such a filter bank leads to higher compression results for images containing ...
    • Subband domain coding of binary textual images for document archiving 

      Gerek, Ö. N.; Çetin, A. Enis; Tewfik, A. H.; Atalay, V. (Institute of Electrical and Electronics Engineers, 1999-10)
      In this work, a subband domain textual image compression method is developed. The document image is first decomposed into subimages using binary subband decompositions. Next, the character locations in the subbands and the ...
    • Vector quantization 

      Çetin, A. Enis; Gerek, Ö. N. (Wiley, 2006)
      Vector quantization (VQ) is a critical step in representing signals in digital form for computer processing. It has various uses in signal and image compression and in classification. If the signal samples are quantized ...